Association between cardiovascular autonomic neuropathy and left ventricular hypertrophy in diabetic haemodialysis patients.

BACKGROUND: Patients with diabetic nephropathy are likely to have neurological complications including cardiovascular autonomic dysfunction, which is related to increased risk of mortality. We investigated whether cardiovascular autonomic neuropathy is associated with left ventricular hypertrophy (LVH) in diabetic haemodialysis patients.
METHODS: Holter electrocardiography was carried out for 24 h with time and frequency domain analyses of heart rate variability in 154 diabetic (age 62+/-11 years) and 63 non-diabetic haemodialysis patients (62+/-10 years). The left ventricular mass index (LVMI) was determined by echocardiography. We used the percentage of differences exceeding 50 ms between adjacent normal RR intervals (pNN50) in time domain analysis and the power in the high-frequency range (HF: 0.15-0.40 Hz) in frequency domain analysis as indicators of parasympathetic activity.
RESULTS: The mean LVMI was greater in diabetic than in non-diabetic patients (168+/-63 vs 144+/-54 g/m(2), P<0.01). LVMI inversely correlated with pNN50 (r = -0.270, P = 0.0007, n = 154) and HF (r = -0.277, P = 0.0005, n = 154) in diabetic patients, but not in non-diabetic patients. By multiple logistic analysis, LVH was strongly associated with pNN50 (odds ratio 0.088; 0, <2%; 1, >/=2%) and HF (odds ratio 0.058; 0, <500 ms(2); 1, >/=500 ms(2)) in diabetic patients.
CONCLUSIONS: Impaired parasympathetic activity, which indicates cardiovascular autonomic neuropathy, was associated with the presence of LVH in diabetic haemodialysis patients. The co-existence of cardiovascular autonomic neuropathy and LVH may be one of the key factors for the high incidence of cardiovascular events in diabetic haemodialysis patients.